The mother of an NYPD cop killed in the line of duty filed a racial discrimination lawsuit Wednesday against a Long Island Pathmark saying managers accused her of trying to use a counterfeit coupon for a free turkey – because she is Vietnamese.

May Schaberger, mother of Alain Schaberger, the Navy veteran cop who was killed while responding to a Brooklyn domestic violence call in 2011, is suing the Islip Pathmark saying employees refused to accept her Shady Brook Farm Turkey coupon – which is given to families of officers who died in the line of duty.

She was shopping at the supermarket on Islip Avenue near Union Boulevard — the same store that accepted her coupon in years past — on Nov. 19, according to her Suffolk County suit.

Two managers allegedly accused the 63-year-old mother of having downloaded the coupon from the internet even after she showed them an NYPD family member ID and a letter from the turkey company.

They treated the East Islip resident “as if she were a common criminal committing fraud, even after she presented her NYPD family survivor ID card,” the suit alleges.

The manager allegedly “spoke loudly and slowly” to Schaberger “as if she was stupid and did not understand English,” according to court papers. He ultimately would not accept the voucher.